Gerard Butler has revealed his character Mike Banning may struggle to save the world in new movie 'Angel Has Fallen'.

The 'Olympus Has Fallen' star is set to return as the US Secret Service agent in the third instalment of the action franchise and has spilled the beans on some of the top secret plot details.

The 47-year-old actor told Den Of Geek: ''This is as similar as maybe Logan was to 'Wolverine', it's definitely a Mike Banning who's almost - as I am now, Gerry Butler for his action career - a Mike Banning who is paying the price of all these years, all the 'Olympus Has Fallen's and 'London Has Fallen's.

''He's paying the price for that physically now and he's struggling a bit in the job. It's no longer the kind of superhero Mike Banning, but it's a guy who's on a more challenging journey and then on top of that everything turns against him when he gets set up for this assassination attempt on the President.

''And some of those facts that he's already struggling with are used against him and he ends up going on the run and is trying to elude the bad guys - and the good guys - and find out who the hell is behind all of this.''

The 'How To Train Your Dragon' star also produces the franchise, which first saw him play action-hero Mike in 2013's 'Olympus Has Fallen', saving Washington from a terrorist invasion.

The 2016 sequel 'London Has Fallen' was set during the US president's visit to the UK capital and the latest film 'Angel Has Fallen' is believed to be centred around Air Force One, the presidential aircraft.

Butler admitted that for a long time he was unsure how to follow-up the sequel.

But he now believes the latest in the trilogy could be even better than the first two movies, having teamed up with stuntman-turned-director Ric Roman Waugh.

He said: ''I couldn't even see a way to make a third, you know we'd joke about it 'What, Tokyo? Hong Kong? What is it going to be!?' and it would be, for sure, what is it going to be? Until this idea came along and until Ric came along - now I've gone from not knowing what to do with it, to thinking this is going to be the best one.''